Coatings for the traffic bearing surfaces of grating



July 21, 1959 H. NAGIN i COATINGS FOR TRAFFIC BEARING SURF'CESl OF GRATING Filed Sept.` 16 1954 2 Sheets-Sheet 1 l l l FIG. 2

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Haro/d July 21, 1959 H. NAGIN 2,895,389

v coATINGs FoR THE TRAFFIC BEARING suRFAcEs 0R GRATING Filed sept. 16 1954 2 sheets-sheet 2 Y wmp 1N V EN TOR.

Y ,L/afp/o/ /hn BY COATINGS FOR THE TRAFFIC BEARING SURF ACES F GRATING Harold Nagin, Pittsburgh, Pa., assigner to Reliance Steel Products Company, McKeesport, Pa., a corporation 0f Pennsylvania Application September 16, 1954, Serial No. 456,380 2 Claims. (Cl. 94--5) This invention pertains to traiiic bearing gratings used ,interiorly and exteriorly and more specifically to a method of treating such gratings to provide .the traffic bearing surfaces with a wear resistant anti-skid surface.`

t Metal gratings of various designs and strength are now comonly used on roadways, bridges, steps, walk ways of all sorts and for many other diverse purposes. The metal wears smooth and when wet or coated with ice or snow becomes hazardous for both vehicular and pedestrian traitic. The present invention overcomes in large degree the tendency of ice to adhere to and wear smooth on the trac bearing surfaces of the grating. The wear resistant abrasive surface provided by the invention is effective to provide better traction under all weather conditions. Y

An object of the present invention is to provide a wear resistant coating to the traffic bearing surfaces of grating and in such a manner as to resist displacement of the coating from such grating surfaces.

Another object of the invention is toprovide such a coating to the tratc bearing surfaces of grating as will present an abrasive surface to the tratlc such as to reduce slipping of the traic moving thereover.

Another object of the invention is to provide such a coating for the tratc bearing grating surfaces and to apply the coating in such manner as to also resist corrosion.

Another object ofthe invention is to provide an economical method for applying such coatings so as to provide for uniformity in the coating and a strong bond between both the coating and the metal and between the coating and abrasive material imbedded therein.

In the drawing forming part of this disclosure, Fig. 1 shows a plan view of a portion of one form of grating with the coating applied thereto;

Figs. 2 and 3 show sections through the grating of Fig. 1 taken on lines II--II and III-III;

Fig. 4 shows a portion of another form of grating with the coating applied thereto;

Figs. 5 and 6 show sections through the grating of Fig. 4 taken on lines V-Vfl and VI-VI thereof; and

Fig. 7 shows an enlarged section through one of the grating members illustrating the coating and bonded abrasives.

In practicing the present invention the speciiic form of the grating and the method of securing the grating members together forms no part of the invention. Any form of welded or riveted grating may have the coating of the invention applied thereto. Since only the traffic bearing surfaces .of the grating cause slipping of the veited' States Patent "ice 2,895,389 Patented July 21, 1959 hicular or pedestrian traflcmoving thereover, the full effectiveness of the coating may be obtained by merely placing the coating on and adjacent such traffic bearing surfaces of the grating. n By continuing the coating across the tratiic bearing surfaces and along the adjacent surfaces of the grating I have found that the coating is better enabled to resist displacement from the traic bearing surfaces and assists in clearing the grating traffic bearing surfaces of skim ice. In the case of riveted grating the most vulnerable portion of the grating as regards corrosion is found around the area where the rivet passes through the grating members. I have found it advantageous in the case of rivet grating to continue n the coating down the sides of the grating members to mercially suitable resins having suitable viscosities for my purposes are available under the trade names Epon Nos. VI and 828. `These are typical and not exclusive examples.

To cure these resins it is necessary to use a catalyst which is introduced at the time the resin is used, and which remains in the cured resin. These catalysts are in the class of polyamines, such as diethylene triamine, ethylene diamine, dimethylamino-propyl amine, diethyla mino-propyl amine, piperidne, and pyridine. Different catalysts may affect the curing time or temperature ref quired to cure the resin, and the amount of catalyst will also vary the curing time. I have found `diethylene triamine to be satisfactory and about 10% by weight of catalyst to resin in the mix is satisfactory. v

Some resi1iency,.without loss of adhesive qualities, may be imparted to the epoxy resins by adding thereto natural or synthetic rubber which may be in granular or latex form. Thus polyvinyl acetate latex, natural rubber latex, latex forms of synthetic rubbers or granular forms of natural or synthetic rubber may be added to the epoxy resins to produce a resin when cured having the characteristics of both. Thus a mixture in the approximate proportions by weight of 1 lb. of Epon VI to 2.5 oz. of catalyst to 3.5 oz. of rubber ofthe forms noted produces a satisfactory base coating for use with a second coating of wear-resistant epoxy resin, catalyst and abrasive material. For this second coat a mixture of one part by volume of Epon 828 plus 10% by weight of a catalyst, with 10 parts by volume of sand and the whole thoroughly mixed, proved satisfactory. The proportions of sand may be greatly reduced if desired, but preferably to not less than equal volumes of sand and resin plus catalyst. When the sand is reduced below this point, the coating tends to lose its abrasive qualities as the sand tends to become wholly embedded in the resin. On the other hand where the sand is; in excess of a proportion of 1 to 1 with the resin, the excess sand provides an abrasive coating with the individual grains of said coated with the resinand adhered together. In this latter case, a more wear-resistant abrasive coating may be provided by pressing granular gritty material onv to the said' coa-ting. before the resin cures. Thus aluminumoxide, spent` grit blast shot, etc.. may be pressed into engagement with the resin coated sand and becomes embedded therein when the resin cures.

The herein disclosed manner of applying the coating has many advantages. The epoxy resins are quite expensive and therefore should be applied only to the areas of the grating where they will be effective for the intended purposes. The coating material is applicable by spraying methods but thisis wasteful of the material. Should, the coating :be applied only 'to the surfaces in thevplane ofr engagement by traflic moving over the grating,- relatively sharp edges might cause destruction of the coating by vehicles striking4 these corners or edges. By"lapping the coating'a short distancev over the sides of the gratingy members, a better wearing bond between the coating'and the metal is provided. The coating has a distinct advantage in that it is water-repellant after thematerial is cured so that water does not readily wet its surface. This improves its traction qualities, and ice forming on the 'surface readily breaks away.

The v'surface of the metal is suitably prepared before applying the coating. This may be done by shot or grit blasting, -use of solvents. pickling, etc. While the resin will adhere tightly to clean metal, the presence of scale, grease and other foreign matter will impair the bonding of' the resin to the metal. Grit blasting imparts a slight roughness to the surface 'of theV metal and improves the eifectiyeness off the bond. Since the resin will also bond very rapidly toits self, the 'entire grating may be made corrosion proc-f' by applyingk thereto any of the commercially 'available paints containing such resins and sold as an Epon paint. The presence ofthe resin causes the paint coat to adhere tenaciously to the metal and being water repellent, the corrosion resistant qualities of the pain-t are greatly increased.

After preparing the grating in the manner described, the grating may be inverted to face its traic bearing surface downward and is pressed into the coating medium previously described. The coating material may be maintained in any suitable container large enough to receive the section of grating to be coated. `Under some conditions some of the resins may need heating so that the container should be so constructed to permit applying heat tothe coating when4 necessary. The downwardly facing traic bearing surfaces of the grating are then pressed into the coating material so that the material flows upwardly along the vertical faces of the grating members about one half inch so as to lap the coating aroundv theedges of thel membersv as shown in the accompanyingl drawings. Where a double coating is applied as hereinbefore described, the rst coat is permitted to cure before the second coating is applied.

Example The grating after being suita'bly cleaned and/or painted was l'dipped into a bath ofresin, catalyst and rubber latex. The grating upon being removed from the bath was stored until the resin cured. This curing time war` about one hour. After curing the grating was then dipped into a bath of the second coating material comprised of resin, catalyst andy sand'. The grating after being removed from the'ba'th was then pressedinto a bed of granular abrasive material such as aluminum oxide, spent grit blast or other suitable material.` This abrasive material is thus forced into the second coating material and becomes imbedded therein.` The grating is then stored to permit curing of the coating whichtakes about one hour. Fig. 7 of the drawings shows l2l typical section through a grating memberrillustrating howthe abrasive material becomes irnbedded in the coating and is bonded therein as the resin cures, The total thickness of the coating resin mixture is preferably about one sixteenth of an inch. The overall thickness of the coating will be increased by the abrasive material.-

4 Example II YThe grating after *being suitably cleaned` and/ or coated with an Epon paint, was dipped into a bath of resin, catalyst and sand until a coating of about one sixteenth thickness was applied to the traiiic bearing surfaces of the grating and around the edges of the grating members as in Fig. 7 of the drawings. The grating was then pressed into the bed of abrasive materials, as before, and the coating allowed to cure. This curing time was about one hour.

Example III The grating after being suitably cleaned as before was dipped into a bath of the resin, catalyst and sand. The proportionsgof sand-,to resin being about one to one. The coating was about one sixteenth inch thick and applied as shown in Fig. 7 of the drawings. The coating was then allowed to cure for one hour.

Referring now to the drawings, Figs. 1 to 3 inclusive are intended to show generally a representative type of welded grating having longitudinally extending bars 1 of any desired shape which are joined at spaced intervals by cross bars 2. These cross bars may be of any suitable shape and welded to the longitudinal bars in any suitable manner. The coating shown applied to the grating longitudinal and cross bars comprises the traffic bearing surface 3` and side portions 4 extending down over the sides of the grating members 1 and 2. The abrasive particles 5 are shown4 by Figs. 7 `as embedding in and cured into the resin coating. The resin coating material being water repellent, extension oftheV coating material over the sides of the grating members helps the grating to dry out quickly and causes ice forming thereon to break away readily.

The grating shown in Figs. 4 to 6 inclusive of the drawings represeints a typical form of riveted grating. Here thelongitudinal bars 6 may be of any suitable design and are connected at intervalsrby suitable transverse connecting members 7which may be of any desired design, the members 6 and 7 being connected by rivets 9. The coating 8 in theiguresvis applied in the same manner as to Figs. 1 to 3 inclusive. It will be noted however that in Figs. 4 to 6 inclusive the coating 8 seals the joints between the members 6 and 7. The coating may also extend over the rivet heads 9 where desired to corrosion proof these members. However, where as previously described the grating is painted with an Epon paint before applying the coating or coatings, the Epon paint provides a corrosion resistant protection for the rivets.

The invention hereindisclosed may be practiced by using an under coat of rubber bearing resin and an outer coat of abrasive bearing resin. The under coat may also have sand or other abrasives added thereto in any desired amount. The examples used herein are therefore by way of illustration and not limitation in the practice of my invention and I do not intend to limit myself to any specic mode of practicing the invention except as made necessary by the scope of the appended claims.

I claim:

l. An open mesh metal grating having anti-slipping traffic bearing surfaces, comprising interconnected metal members having their upper surfaces in substantially the same plane to provide traffic bearing surfaces and side surfaces extending downwardly from the traiic bearing surface, a mixture of one part by volume of liquid epoxy resin plus4 about 10% by weight of a catalyst and not less than one part by Volume of sand-like abrasive particles applied as a continuous coating of substantial thickness over the exposed traic bearing surfaces, the joints therebetween and a substantial portion of the adjacent exposed .side surfaces of the said interconnected metal members.

2. The grating as defined in claim l wherein additional larger abrasive particles are partially embedded in the coating material before curing.

(References ou following page).

5 References Cited in the le of this patent 2,246,898 UNITED STATES PATENTS 2302586 2,317,960 142,728 Reagan Sept. 9, 1873 2,317,963 853,034 R'U May 7, 1907 2,506,486 1,156,081 Hopp Oct. 12, 1915 2,512,996 1,292,535 Sweetland Ian. 28, 1919 2,535,794 1,665,846 Denni Apr. 10, 1928 2,637,715 1,868,107 Lachman July 19, 1932 2,668,484 1,953,337 Carson Apr. 3, 1934 10 2,705,223

6 Sayre June 24, 1941 Thelen Nov. 17, 1942 Sayre Apr. 27, 1943 Bashore Apr. 27, 1943 Bender et al. May 2, 1950 Bixler June 27, 1950 Hempel Dec. 26, 1950 Ott May 5, 1953 Bustin Feb. 9, 1954 Renfrew Mar. 29, 1955 

